1. Field of the Invention
A plasma display panel (PDP) having a structure of opposed discharge and that is capable of reducing power consumption and improving exhaust efficiency.
2. Description of the Related Art
A PDP displays an image by using visible light generated when vacuum ultraviolet rays radiating from plasma generated by a gas discharge excite a phosphor material. The PDP enables extra-large screens of larger than 60 inches to be thinner than 10 cm. In addition, the PDP is a self-emissive display device like a cathode ray tube (CRT), and has excellent capacity for reproducing colors and without distortion at various viewing angles. The PDP has advantages of greater productivity and lower cost due to a simpler method of manufacturing than for a liquid crystal display (LCD), and is spotlighted as the next generation industrial flat panel display and home TV display.
The structure of the PDP has been developed for many years, since the 1970s, and the generally-known structure now is a three-electrode surface discharge PDP. The three-electrode surface discharge PDP includes one substrate that includes two electrodes arranged on the same surface, and another substrate that is arranged at a certain distance therefrom and includes address electrodes extending in a perpendicular direction. A discharge gas is filled in the space between the pair of substrates and the substrates are sealed against each other.
Generally, whether or not the discharge occurs is determined by the discharge of scan electrodes that are connected to each line and independently controlled, and address electrodes facing the scan electrodes. In addition, sustain discharge that displays brightness is generated by two electrode groups, namely sustain electrodes and scan electrodes, that are located on the same surface.
When a discharge occurs between the sustain electrodes and the scan electrodes, a voltage distribution between the sustain electrodes and the scan electrodes shows a distortion due to a space charge effect that occurs at dielectric layers around the sustain electrodes and the scan electrodes. More specifically, in an AC three-electrode surface discharge PDP, a sustain electrode and a scan electrode operate alternately as an anode and a cathode, and thus a voltage distribution between the anode and the cathode becomes distorted.
That is, a cathode sheath is formed around the cathode, an anode sheath is formed around the anode, and a positive column is formed therebetween. Most of the voltage that is applied between the anode and the cathode is consumed by the cathode sheath, part of the voltage is consumed in the anode sheath, and little voltage is consumed in the positive column. It is known that electron heating efficiency in the cathode sheath depends on a secondary electron emission factor of a protective layer (typically a MgO layer) formed on the surface of a dielectric layer, and most voltage that is applied is consumed to heat electrons in the positive column.
Vacuum ultraviolet rays that collide with phosphor and produce visible light are generated during a transition of xenon (Xe) gas in an excited state into a stable state, and the excited state of xenon is provided by collision of xenon gas with electrons. Therefore, in order to increase a ratio of voltage generating visible light to voltage applied (that is, radiation efficiency), the ratio of voltage contributing to a discharge of xenon gas to voltage applied (that is, discharge efficiency) should be improved, and in order to improve the discharge efficiency collisions of xenon gas with electrons, electron heating efficiency should be improved.
Although most of the applied voltage is consumed in the cathode sheath, the electron heating efficiency is low. In the positive column, little of the applied voltage is consumed and the electron heating efficiency is very high. In addition, the cathode sheath and the anode sheath occupy a nearly constant space regardless of a distance between the sustain electrode and the scan electrode. Therefore, in order to accomplish high discharge efficiency, the positive column should be enlarged, and in order to enlarge the positive column, a PDP that has an opposed discharge structure and that is capable of increasing the distance and the opposing area between the sustain electrode and the scan electrode is needed.
A typical PDP has low exhaust efficiency and thus has various problems. In other words, when the exhaust efficiency is low, impurities generated during a discharge continue to remain in discharge spaces. Therefore, what is needed is a design for a PDP that improves discharge efficiency and exhaust efficiency while being easy to make.